This revised R01 application seeks to prospectively study predictors of changes in alcohol use across three transitional periods in young adulthood (early-, middle-, and later-young adulthood). Epidemiologic data indicate that the peak period for alcohol use and alcohol disorders occurs between ages 18-25 years, with reductions in use following this age interval. Maturing out, i.e., as individuals assume adult roles (e.g., marital partner, full-time employee), has been proposed as an explanation for these behavioral changes. The limited number of studies evaluating maturing out of alcohol use have yielded mixed findings, with some supporting overall reductions in use whereas other studies suggest substantial heterogeneity. This R01 application proposes to use a 23-year, seven-wave longitudinal dataset, with an age range of 15-34 years to examine adolescent and young adult predictors of changes in alcohol use across young adulthood. Multisource data from young adults, their spouses, and their parents will be used to investigate the role of interpersonal factors (e.g., conflict, support) and young adult alcohol use in the marital and family context. Work-related and interpersonal stressors will also be investigated as joint predictors of changes in alcohol use. Several different analytic techniques (e.g., latent growth models, latent growth mixture models, latent transition models) will be used to evaluate changes in alcohol use across YA transitions.